1. Field of the Invention
This invention relates to a punch apparatus and more particularly to an apparatus for preparing elongated multiflanged extrusions for use in conjunction with fiberboard air handling ducts.
2. Description of the Prior Art
Air handling ducts of the type employed in heating and refrigeration systems have traditionally been formed of sheet metal, with a recently developed alternative being to form the ducts of insulative fiberboard. In many instances, the fiberboard ducts have an advantage over metal ducts due to such factors as weight, insulative properties, cost, and the labor involved.
However, fiberboard ducts have not achieved the acceptance they deserve due to the problems of assembling individual lengths of ducting and of interconnecting adjacent lengths thereof.
The fiberboard material employed in the air handling ducts is supplied in sheets, with the individual lengths of ducting being formed by longitudinally folding the sheet so that its opposite side edges are in contiguous abutting contact with each other and the resulting duct is either of square or rectangular cross sectional configuration. The abutting side edges of the fiberboard material are sealingly interconnected with tape, and the assembly of individual lengths of ducting into a complete duct system is accomplished in a similar manner by interconnecting adjacent lengths of the ducting with tape.
The use of tape as an assembly and closure material has, in many instances, been found to be unsatisfactory due to temperature, pressure and other factors causing the tape to lose its adhesive grip on the fiberboard material which, of course, will cause leakage of the duct system and in some cases can allow complete collapsing of the system.
Elongated multiflanged extrusions are now being employed in place of the above described tape for assembly and closure of the fiberboard ducts. Extrusions for this purpose are disclosed in U.S. Pat. No. 3,677,579, issued on July 18, 1972 to W. N. LaVanchy.
Briefly, a first type of extrusion, sometimes referred to as a longitudinal extrusion, is being employed for sealingly interconnecting the side edges of the fiberboard sheet to form the individual lengths of ducting.
Other configurations of extrusions, as determined by the type of interconnection desired, are being employed on the open ends of the individual ducts to facilitate interconnection of adjacent lengths of ducting. These latter extrusions may be referred to as joint extrusions.
Due to the great variations in lengths and cross sectional sizes of ducts, the above described extrusions are supplied in straight pieces which are individually prepared for installation and assembly when the specific sizes and configuration of the ducting are known.
Therefore, the longitudinal extrusions must be cut to the proper length and also must be provided with a recessed notch at each of their opposite ends to allow assembly of the joint extrusions to the fiberboard ducting.
The joint extrusions, which are also supplied in straight pieces, must be notched in specific locations along the length thereof to allow these extrusions to be bent into either the square or rectangular configuration suitable for mounting on the ends of the ducting. Also, the joint extrusions have a hanger flange which allows the assembled duct system to be suspendingly mounted therefrom. The hanger flange must be punched or otherwise provided with hanger holes at the proper locations.
Notching, cutting, and otherwise preparing the multiflanged extrusions for use with the fiberboard ducts is, in some instances, being accomplished with hand tools. Obviously, this is a very tedious, time consuming, and costly method, so a prior art apparatus for accomplishing these tasks was developed.
This prior art apparatus is a complex, slow operating and inadequately designed machine which has achieved only limited acceptance for those reasons as well as the cost which has placed this apparatus beyond the economic justification of many companies doing this sort of work.
Therefore, a need exists for a new and improved extrusion preparation apparatus which overcomes some of the problems of the prior art.